1. Technical Field
Exemplary aspects of the present invention generally relate to a belt assembly including an endless looped belt entrained about a plurality of rollers and an image forming apparatus, such as a copier, a facsimile machine, or a printer including the belt conveyor unit.
2. Description of the Related Art
In known image forming apparatuses, an image bearing member such as a latent image bearing member and an intermediate transfer member for carrying an image and a conveyor system for carrying a sheet-type medium employ an endless looped belt. A belt assembly including such an endless looped belt also includes a plurality of support rollers, and the belt is entrained about and stretched taut at a certain tension between the plurality of support rollers. The plurality of support rollers is arranged at predetermined shaft intervals. Normally, one of support rollers constitutes a drive roller to rotate the belt. In many cases, one of support rollers constitutes a tension roller biased against the belt by a biasing device, thereby applying a desired tension to the belt.
After extended use, the belt deteriorates gradually due to wear and tear, and contamination, and loses its intended function eventually. As a result, after a predetermined time period, the belt needs to be replaced with a new belt as needed. Because other parts constituting the belt assembly such as the plurality of support rollers, a shaft retainer to hold end portions of rotary shafts of the support rollers have often not reached the end of their product life cycles by the time the belt needs to be replaced, the belt needs to be detached from the belt assembly and then the new belt is mounted.
When replacing the belt with the new one, the tension of the belt is loosened so that the belt is detached from the support rollers. More specifically, the rotary shaft of one of the support rollers about which the belt is entrained is moved to loosen the belt tension, thereby allowing the belt to be detached from the support rollers.
For example, the distance between the shafts of two support rollers is shortened so that the tension of the belt is loosened and detached from the support rollers. In this configuration, a device to change the position of the support rollers is necessary, resulting in an increase in the number of parts and the cost and hindering efforts to make the belt assembly compact.
In view of the above, there is demand for a belt assembly capable of easy installation and detachment of the belt without increasing the number of parts, and image forming apparatus including such a belt assembly.